How do you measure maturity? It is not a function of how old you are—society is dominated by multiple generations of immature adults who refuse to act their age. Maturity is tested by time, but it’s not a question of how long a person has lived. Rather, it’s determined by how wisely he or she lives.

The same is true in the spiritual realm. It doesn’t matter how long a person has sat under the teaching of God’s Word if his life is still dominated by fickle emotionalism, foolish worldliness, and shallow spirituality. Exposure to the Word alone won’t make us mature Christians—we must be faithful and disciplined to put it to work in our lives.

Put simply, spiritual maturity is the process of learning to discern. In fact, the path to real discernment is the path to spiritual growth—and vice versa. Growth in grace is an ongoing process throughout this earthly life. No Christian ever reaches complete maturity this side of heaven: “Now we see in a mirror dimly, but then face to face; now I know in part, but then I will know fully just as I also have been fully known” (1 Corinthians 13:12). We must continually “grow in the grace and knowledge of our Lord and Savior Jesus Christ” (2 Peter 3:18). We should hunger “for the pure milk of the word, so that by it [we] may grow” (1 Peter 2:2).

As we mature, our senses are exercised to discern good and evil (Hebrews 5:14). As we cease to be children, we gain stability (Ephesians 4:14-15). Mature people are discerning people.

We know this from the natural world. The bulk of every parent’s responsibility is training children to be discerning. We continually do it, even when our kids become teenagers. We help them think through issues, understand what is wise and unwise, and prompt them to make the right choices. We help them discern. In fact, the goal of parenting is to raise a discerning child. It doesn’t happen automatically, and it doesn’t occur without diligent, lifelong instruction.

The same is true spiritually. You don’t pray for discernment and suddenly wake up with abundant wisdom. It is a process of growth.

Stay on the path of maturity. Sometimes it involves suffering and trials (James 1:2-4; 1 Peter 5:10). Often it necessitates divine chastening (Hebrews 12:11). Always it requires personal discipline (1 Timothy 4:7-8). But the rewards are rich:

How blessed is the man who finds wisdom and the man who gains understanding. For her profit is better than the profit from silver and her gain better than fine gold. She is more precious than jewels; and nothing you desire compares with her. Long life is in her right hand; in her left hand are riches and honor. Her ways are pleasant ways and all her paths are peace. She is a tree of life to those who take hold of her, and happy are all who hold her fast. . . . My son, let them not vanish from your sight; keep sound wisdom and discretion, so they will be life for your soul and adornment for your neck. Then you will walk in your way securely and your foot will not stumble. (Proverbs 3:13-18, 21-23)

And these riches, unlike diamonds, will retain their value and brilliance for all eternity. The alternative is a life of theological confusion, where spiritual treasures are confused with spiritual fakes.

Whoever is wise, let him understand these things; whoever is discerning, let him know them. For the ways of the Lord are right, and the upright walk in them, but transgressors stumble in them. (Hosea 14:9)

Hosea saw discernment as necessary for righteousness, and antithetical to those who transgress God’s law. That’s why wisdom is so essential if we want to please the Lord through the way we live. If we are to continually grow in conformity to Christ, we cannot afford to stagnate in our discernment. It must be our lifelong pursuit.